Lamb with potato and celeriac rosti

First make the rostis. Place potato, celeriac and onion in a clean cloth and squeeze out as much water as possible. Shape into flat patties and reserve. Brush lamb fillets sparingly with Tabasco sauce. Heat 1tbsp oil in a pan and sear and brown lamb fillet on all sides. Cook for around 5 mins, rolling around to brown all over but keeping pink inside. Cook longer if you prefer, then leave to rest. Fry rostis in remaining oil until browned and crisp on both sides then lightly splash with Tabasco. At the same time, cook vegetables in lightly salted boiling water until just tender. Drain and reserve with a little butter melting over. Place a rosti on each plate then slice the lamb fillet thickly and perch on top. Arrange vegetables around it and pour lamb juices over.